thank you for the report. Working with 0face objects, double-face polygons, obscure 4vertex triangles or degenerated meshes causes inevitably a crash during the production - the question is only where. Since FlatIron was originally made for game engines, it has the preemptive buffer to react very sensible of all errors done by 3d modler or by some strange import/export geometries from other applications. Best known are CAD tools for architects, working in world-scale 0.01cm and then importing this into Max Inch and then rescaling it. Almost in all cases the degenerated geometries will cause:- crash in FlatIron- Rendering Errors in Vray/Mray with GI or any other fine rendering calculation (reflections, refractions etc)- problems by exporting it to other applications- wrong UVs- etc.

We will definitely cover some of degenerated issues in the next release, to ignore such behavior, yet it can have an strong impact on the quality of UV Unwrap - 0face face still has a dimensions in a world space and can cause strange artifacts in the map).

Best way, of course, is to work tidy and to avoid creating bad meshes. There is whole science in the last years made of proper modeling techniques and mesh-design, there are numerous tools and scripts on the market doing "Mesh-Clean" - i myself use them on regular basis (we get many models from apprentice workers or outsourcing studios where it is clear by observing the model that the artist didn't learn well his job - Mesh-Cleaners are life-saver